Carburetor construction



Get. 9, 1956 R. B. HIGGINS, JR

CARBURETOR CONSTRUCTION Filed March 4, 1952 2 Sheets-Sheet 2 &

2,766,025- CARBURETOR CONSTRUCTION Rene B. Higgins, Jr., Willits, Calif. Application March 4, 1952, Serial No. 274,705 1 Claim. (Cl. 26172) This invention relates to carburetors and particularly to carburetors which are adapted to be used on portable devices such as similar devices which must be in many different positions.

I have found, for example, that the use of certain chain gasoline engines is restricted by certain factors, one of the most important of which is the inability to operate the saw at angles in excess of forty five degrees.

erator to stand on the log and cut through the same with the saw chain swinging through an arc from horizontal to substantially vertical position.

I have found that certain saws may not be operated at angles in excess of forty-five degrees to the horizontal for the reason that the carburetor at those angles will not suppiy fuel to the engine which drives the saw.

It is an object of this invention to provide a carburetor which will feed fuel to the engine when the saw is being operated at angles up to and including ninety degrees or, in a vertical position.

it is a further object of this invention to provide a device of this character which is simple to manufacture, foolproof to operate, and easy to service.

Other objects and advantages of this invention will appear from the following specification, taken in conjunction with the accompanying drawings in which:

Figure 1 is a plan view of a chain saw incorporating my invention;

Figure 2 is an enlarged detail of Figure 1 showing the mounting of a carburetor upon a chain saw engine;

Figure 3 is a view taken along the line 3-3 of Figure 2 showing the carburetor bowl and our fuel supply tube;

Figure 4 is a top plan view taken along the line 44 of Figure 3; and

Figure 5 is a view similar to Figure 3 in which the carburetor is shown in tilted position.

As illustrated in Figure l, the conventional chain saw is provided with and driven by an engine which, through a suitable clutch, not shown, serves to drive an articulated member or chain 11. The chain 11 is formed of a number of links which are provided with radially extending cutting teeth and is supported by a guide rail about which it is driven. The lower run of the chain 11 engages the material being cut.

The engine 10 is a conventional gasoline driven in ternal combustion engine and is provided with a carburetor 12. As illustrated particularly in Figure 3, the carburetor body is provided with a bowl 13 and the necessary air and fuel passageways and a flange 14 by which it may be secured to a manifold 16.

The operation of such a carburetor is well understood way 18 is provided with a restriction which forms a valve seat 19.

The supply of gasoline or fuel to the bowl 13 through the passageway 18 .is controlled by the operation of a valve 21 which operates against valve seat 19. 21 is provided with into the bowl 13 and supports a float 23. The float 23 the operation of the valve 21 may be varied to respond to diiferent quantities of liquid within the bowl 13.

In a conventional carburetor the fuel passes from the bowl 13 through a passageway 20 in the side wall of the mainder of the carburetor 15 well known.

It will be noted, however, that in addition to the orifice and passageway as previously described herein, I have provided a tubular extension member 24 into the bowl 13 and, as illustrated in Figure 4, extends substantially the full the open end of the tubular member 24 is below the sur- By suitably locating the position of the float 23 on the apparent that the quantity of fuel flow of liquid to the device. It is obvious that When this occurs fuel will not be supplied to the engine.

To overcome such a diificulty I have provided a spring 26 which surrounds the valve stem 22. The lower end of the spring 26 engages the float 23 and of the spring 26 engages the cover 27 of the bowl 13. The spring 26 is of necessity of light construction inasnot be strong enough to overcome the when the carburetor is in a position approximating that illustrated in Figure 3. It is apparent that should the spring be too strong, the use of the float would be destroyed. However, the spring must be sufliciently strong that it will balance the weight of the float and keep the valve 21 open when the carburetor is in the position illustrated in Figure 5. The particular spring which I have found useful in this operation is one which is one-half inch in length and consists of sixteen turns of .0075 spring steel Wire.

Operation of the device may briefly be described as follows: Let it be assumed that the saw is to be operated in horizontal position in which event the carburetor will occupy the position illustrated in Figure 3. The fuel within the bowl 13 is at the level indicated by the dotted line. When the saw, engine and carburetor are in the position thus indicated, gasoline will flow through the bowl 13 and the tubular member 24 to the jets to be drawn into the air stream where it will be mixed with proper quantities of air to form a combustible mixture. The carburetor will continue to supply gasoline to the engine for as long as fuel is fed through the tube 24.

However, let it be assumed that the saw is tipped in its operation to a position at which the carburetor occupies generally the position illustrated in Figure 5. This, it will be recalled, is the position which the carburetor will occupy when the saw is tilted to a perpendicular position. It is apparent that the tube 24 will still penetrate the body of fuel within the bowl 13 with the result that the same will be supplied to the engine and the engine will continue to operate. It is apparent that if the tube 24 was not present, no gasoline would be supplied to the engine with the result that the same would cease to function.

It is apparent also that when the carburetor is in the position illustrated generally in Figure 5, the float 27 will cease to operate in a normal manner and it will be caused to move to the right or to the left, as viewed in Figure 5, and to open and close the valve 21, not in response to the quantity of liquid within the bowl 13 but in response to vibration, gravity, etc. To prevent the valve 21 from closing against the valve seat 19 and thus prevent the flow of fluid into the bowl 13 I have provided the spring 26, which, as has been previously described, will serve to maintain the valve 21 in open position and assure the flow of gasoline to the bowl 13.

It is apparent from the foregoing that I have provided a carburetor, which, when secured to the engine of the chain saw, as illustrated in the accompanying drawings, would permit the chain saw to be operated in any position from the horizontal to the vertical.

Saws of this type are customarily provided with some means by which the chain and its guard may be removed and replaced at a different angle so that horizontal, as well as vertical sawing may be accomplished. This ren' ders it unnecessary to provide a carburetor which is capable of operating in positions where it is tilted about the longitudinal axis of the tube 24.

My invention is particularly adapted for tilting of the saw in a plane defined by the guard of the saw. It will be noted in this regard that the tubular member 24 is parallel to the direction of travel of the saw.

I claim:

In a carburetor adapted for use in a plurality of positions about a lateral axis of rotation, a bowl, means for controlling the flow of gasoline into said bowl, said means including a valve seat in the bottom of said bowl, a valve adapted to cooperate with said valve seat, a stern mounted on said valve, means carried within the bowl for allowing reciprocation of said valve stem along its longitudinal axis, comprising a float mounted on said stem, said float being responsive to the level of gasoline in said bowl when said float is in a substantially horizontal position, a spring mounted on said stem, said spring being of insuflicient strength to prevent the normal operation of said float when the same is responsive to the position of gasoline within said bowl, but of sufficient strength to hold said valve in an open position when said bowl is tilted to a position in which the float is not responsive to the quantity of gasoline within said bowl, and means for feeding gasoline from said bowl to an engine, said means including a tubular extension member extending into the bottom of said bowl at right angles to said axis and having its open end in that portion of the bowl containing gasoline when the carburetor is tilted from the horizontal in one direction about said lateral axis.

References Cited in the file of this patent UNITED STATES PATENTS 

